Apperception (Latin ad + percipere, to perceive) has the following meanings:

In epistemology, it is "the introspective or reflective apprehension by the mind of its own inner states" (Ledger Wood in Runes).

In psychology, it is "the process by which new experience is assimilated to and transformed by the residuum of past experience of an individual to form a new whole" (Ledger Wood in Runes). In short, it is to perceive new experience in relation to past experience.

Example 1: We see a fire (visual perception). By apperception we correlate the appearance of fire with past experiences of being burned. Having combined present and past experience we realize this is a situation in which we should avoid placing our hand in the fire and being burned.[1]

Example 2: A rich child and a poor child walking together come across the same $10.00 bill on the sidewalk. The rich child says it is not very much money and the poor child says it is a lot of money. The difference lies in how they apperceive the same event -- the lens of past experience through which they see and value (or devalue) the money.[2]

Henry Murray used the term "apperception" to refer to the process of projecting fantasy imagery onto an objective stimulus. The concept of apperception and the assumption that everyone's thinking is shaped by subjective processes provides the rationale behind the Thematic Apperception Test (TAT). This was developed by Murray and Morgan (1935).

In philosophy, Kant distiguished empirical apperception from transcendental apperception. The first is "the consciousness of the concrete actual self with its changing states", the so-called "inner sense". The second is "the pure, original, unchangeable consciousness which is the necessary condition of experience as such and the ultimate foundation of the synthetic unity of experience" (Otto F. Kraushaar in Runes). See Kantianism.

The eastern concept of the sanskara or samskara can also be looked upon as a form of apperception -- seeing events through the 'lens' of accumulated impressions.